A conventional method of manufacturing a composite optical component is disclosed in Japanese Patent Laid-Open No. 63-225557, Japanese Patent Laid-Open No. 60-243601, and so on. In this method, the joining faces of lenses are bonded to each other with an adhesive, or casting is performed on a glass lens introduced into a die to form a lens on one of the front side and the back side of the glass lens, so that a composite optical component is manufactured.
In this manufacturing method, adhesion decreases over time and exfoliation occurs. Further, defoaming is necessary on the joints. Since problems in reliability and manufacturability occur, manufacturing methods achieving high manufacturability and low cost are disclosed in Japanese Patent Laid-Open No. 8-187793, Japanese Patent Laid-Open No. 8-190004, Japanese Patent Laid-Open No. 11-23809, Japanese Patent Laid-Open No. 2006-126336, and so on.
For example, FIG. 9 shows a state immediately after dies are closed. In a cavity 304, a core lens C acting as an insert is held from above and below by support pins 107 and 207 while being sandwiched between the support pins 107 and 207. To be specific, the core lens C is held by the lower support pins 207 and the upper support pins 107 with an elastic force.
Fixed-side retainer plates 102 are attached to a fixed-side die plate 101 of a molding machine and a fixed-side core 103 is fixed on the fixed-side retainer plates 102. A mounting plate 104 and a driving plate 105 are slidably stored in the fixed-side core 103 in a direction that opens the dies, and the mounting plate 104 and the driving plate 105 are fixed to each other while holding the plurality of support pins 107 and a pressure receiving pin 108 therebetween. Elastic springs 106 are held while being compressed between the driving plate 105 and the fixed-side die plate 101.
Movable-side retainer plates 202 are attached to a movable-side die plate 201 and a movable-side core 203 is fixed in the movable-side retainer plates 202. A mounting plate 204 and a driving plate 205 are slidably stored in the movable-side core 203 in the direction that opens the dies, and the mounting plate 204 and the driving plate 205 are fixed to each other while holding the plurality of support pins 207 and a pressure receiving pin 208 therebetween. Elastic springs 206 are held while being compressed between the driving plate 205 and the movable-side die plate 201. An ejector rod 209 is formed to protrude and retract through a through hole drilled on the movable-side die plate 201, and the end of the ejector rod 209 is disposed to press the driving plate 205.
Resin is injected from a gate 303 to the cavity 304 through inlet holes 301 and 302. Pressure receiving faces formed on the ends of the pressure receiving pins 108 and 208 face the inlet hole 301. Under normal conditions, the support pins 107 and 207 are protruded into the cavity 304 by the elastic forces of the elastic springs 106 and 206. When the core lens C acting as an insert is introduced to be supported by the support pins 107 and the dies are closed, as shown in FIG. 9, the positions of the support pins 107 are kept due to the elastic modulus of the elastic spring 106. The elastic spring 106 has a higher elastic modulus than the elastic spring 206. The elastic springs 206 having a lower elastic modulus than the elastic springs 106 are slightly compressed and the support pins 207 are somewhat retracted. In this way, the core lens C is sandwiched by the support pins 107 and 207 with an elastic force.
When resin is introduced from the inlet hole 301 in this state, the resin fills a space around the core lens C and the pressure receiving surfaces facing the inlet hole 301 are pressed by the injection pressure of the introduced resin, so that the pressure receiving pins 108 and 208 retract and the support pins 107 and 207 retract from the cavity 304.
After that, the resin is cured in a state in which the core lens C floats at the center of the cavity 304, so that resin lenses are formed on both sides of the core lens C.